B5 Communicable Diseases

Question 1

what is a communicable disease?

Answer 1

a disease which can be spread from person to person

Question 2

how are communicable diseases spread?

Answer 2

by pathogens such as bacteria or viruses

Question 3

how do different diseases interact with each other?

Answer 3

one disease can put someone at risk of other diseases

one disease can also cause another

Question 4

what are pathogens?

Answer 4

microorganisms which cause infectious disease

Question 5

what are some examples of pathogens?

Answer 5

bacteria
viruses
protists
fungi

Question 6

how do bacteria make humans ill?

Answer 6

once inside the body, they reproduce rapidly
they can then release harmful chemicals (toxins)
toxins damage tissues and make us feel ill

Question 7

how do viruses make humans ill?

Answer 7

the virus invades the host cell
it then reproduces inside the cell
this is very damaging to the cell and cause it to burst open and die when the virus leaves

Question 8

how do viruses reproduce?

Answer 8

they have to use a host cell

Question 9

how are pathogens spread?

Answer 9

in the air (e.g. water droplets)
directly in water
direct contact by individuals

Question 10

how can the spread of pathogens be reduced?

Answer 10

washing hands before eating
clean drinking water
isolation
vaccination

Question 11

what type of pathogen is malaria?

Answer 11

a protist

Question 12

what is the life cycle of the malaria pathogen?

Answer 12

an infected person is bitten by a mosquito. the pathogen passes into the mosquito.
the mosquito then bites a different person and infects them

Question 13

what is a vector?

Answer 13

another organism which carries a pathogen from one person to another without being infected itself

Question 14

what are the mains ways to stop the spread of malaria?

Answer 14

stop the vector from breeding - drain areas of still water, spray areas with insecticide
prevent mosquitoes biting humans - sleep under mosquito nets

Question 15

give 2 examples of viral diseases:

Answer 15

measles

HIV

Question 16

can antibiotics kill viruses?

Answer 16

no.

viruses cannot be killed by antibiotics

Question 17

what are the symptoms of measles?

Answer 17

high fever

red skin rash

Question 18

how is measles spread?

Answer 18

in droplets when an infected person coughs or sneezes

the virus then passes to a different person when the droplets are inhaled

Question 19

what can happen if someone has measles?

Answer 19

complications can develop
this can cause damage to the breathing system and the brain
it can also be fatal

Question 20

what are young children given to protect them against measles?

Answer 20

a vaccination

Question 21

what are the symptoms of HIV?

Answer 21

a flu-like illness

Question 22

what is the HIV virus doing to the cells in the body?

Answer 22

the virus is attacking the cells in the body’s immune system

this means the immune system becomes severely damaged

Question 23

what happens when the immune system becomes badly damaged?

Answer 23

it cannot fight off other infections that people could normally deal with
it is also unable to fight cancer cells

Question 24

what is the late stage of the HIV called?

Answer 24

the patient is described as having late-stage HIV or AIDS

this is fatal

Question 25

what is the treatment for HIV?

Answer 25

antiretroviral drugs - stops the virus multiplying so it does not damage the immune system these drugs are not a cure and they must be taken by the patient for the rest of their life

Question 26

how is HIV transmitted?

Answer 26

through the exchange of fluids between humans

Question 27

what are some examples of bacterial diseases?

Answer 27

salmonella food poisoning | gonorrhoea

Question 28

what drugs kill bacteria?

Answer 28

antibiotics

Question 29

how is the bacteria causing salmonella food poisoning spread?

Answer 29

by ingesting infected food

Question 30

what causes the symptoms of salmonella?

Answer 30

the toxins released by the bacteria

Question 31

what are the symptoms of salmonella food poisoning?

Answer 31

fever abdominal cramps vomiting diarrhoea

Question 32

what controls the spread of salmonella food poisoning in the UK?

Answer 32

all chicken are vaccinated against salmonella

Question 33

how is gonorrhoea transmitted?

Answer 33

it is an STD

Question 34

what are the symptoms of gonorrhoea?

Answer 34

thick yellow/green discharge | pain when urinating

Question 35

how was gonorrhoea treated in the past?

Answer 35

it was treated with penicillin | however, antibiotic resistant strains of the bacteria are now common

Question 36

what is used to treat gonorrhoea today?

Answer 36

different antibiotics (not penecillin)

Question 37

what can stop the transmission of gonorrhoea?

Answer 37

use a condom - stops bacteria passing from person to person | get tested - they can then be treated and prevent it from being passed on

Question 38

what are some examples of diseases in plants?

Answer 38

virus - tobacco mosaic virus | fungus - rose black spot

Question 39

what are the symptoms of tobacco mosaic virus?

Answer 39

leaves discolour in a mosaic pattern

Question 40

what does discolouration in leaves result in? (from TMV or rose black spot)

Answer 40

the rate of photosynthesis is reduced so the growth of the plant is reduced

Question 41

what are the symptoms of rose black spot?

Answer 41

leaves develop purple or black spots | leaves then often turn yellow and fall off

Question 42

how is rose black spot spread?

Answer 42

the fungus is spread by water or wind

Question 43

what are the ways to treat rose black spot?

Answer 43

fungicides - kills the fungi | remove infected leaves and destroy them

Question 44

what do aphids do to plants?

Answer 44

extract nutrients from the plant, stunting it's growth

Question 45

are insects a pathogen?

Answer 45

no | they do not cause an infectious disease

Question 46

how can you spot diseases on plants?

Answer 46

``` growths spots discolouration stunted growth decay or rot malformed stems or leaves ```

Question 47

how can you identify a plant disease?

Answer 47

use a garden manual or website take the infected plant to a lab to identify the pathogen testing kits containing monoclonal antibodies

Question 48

what happens if there is a lack of the nitrate ion in plants?

Answer 48

it causes stunted growth | this is because nitrate is needed for protein synthesis and therefore growth

Question 49

what happens if there is a lack of the magnesium ion in plants?

Answer 49

it causes chlorosis as magnesium is needed to make chlorophyll the leaves lose their green colouration

Question 50

what features does the physical defence system in plants have?

Answer 50

cellulose cell wall and waxy cuticle - difficult for microbes to penetrate bark - a barrier to entry for microbes

Question 51

what features make up the chemical response in plants?

Answer 51

antibacterial chemicals - kill bacteria | poisons - deters herbivores from grazing on the plant

Question 52

what features make up the mechanical defence system in plants?

Answer 52

thorns - protect from being eaten by herbivores hairs - irritate the mouth of herbivores making it difficult to eat leaves that droop or curl when touched - might scare herbivores mimicry - herbivores think the plant is something else so don't eat it